Surgical patient side cart with steering interface

ABSTRACT

A patient side cart for a teleoperated surgical system can include one or more wheels positioned to support the cart for wheeled motion on a ground surface, at least one manipulator portion for holding a surgical instrument, a steering interface having a grasping portion and comprising a sensor positioned to sense turning, fore, and aft forces exerted on the grasping portion to move the cart, wherein the sensor is in signal communication with a drive control system of the patient side cart, and an additional sensor operatively coupled to the drive control system. The additional sensor may be positioned between the steering interface and the wheels on a side of the cart at which the steering interface is positioned, wherein in response to a force exerted on the additional sensor during backward motion of the cart in response to an aft force exerted on the grasping portion, the sensor sends a signal to the drive control system to stop motion of the cart.

This application is a continuation of U.S. patent application Ser. No.15/073,811, filed Mar. 18, 2016, which is a continuation of U.S. patentapplication Ser. No. 14/208,663, filed Mar. 13, 2014 (now U.S. Pat. No.9,308,937, which claims the benefit of U.S. Provisional Application No.61/791,924, filed Mar. 15, 2013, each of which is incorporated byreference herein in its entirety.

TECHNICAL FIELD

Aspects of the present disclosure relate to a steering interface for auser to maneuver a cart, such as, for example, a teleoperated (robotic)surgical system patient side cart. Aspects of the present disclosurealso relate to a replaceable steering interface for a cart.

INTRODUCTION

Some minimally invasive surgical techniques are performed remotelythrough the use of teleoperated (robotically-controlled) surgicalinstruments. In teleoperated (robotically-controlled) surgical systems,surgeons manipulate input devices at a surgeon console, and those inputsare passed to a patient side cart that interfaces with one or moreteleoperated surgical instruments. Based on the surgeon's inputs at thesurgeon console, the one or more teleoperated surgical instruments areactuated at the patient side cart to operate on the patient, therebycreating a master-slave control relationship between the surgeon consoleand the surgical instrument(s) at the patient side cart.

A patient side cart need not remain stationary in a particular location,such as within one operating room, but instead may be moved from onelocation to another. For example, a patient side cart may be moved fromone location to another, such as from one location in an operating roomto another location in the same operating room. In another example, apatient side cart may be moved from one operating room to anotheroperating room.

One consideration in moving a patient side cart of a teleoperatedsurgical system is the ease with which the patient side cart may bemoved by a user. Due to its weight, size, and overall configuration, itmay be desirable to provide a patient side cart with a drive to assist auser with moving the patient side cart. Such a drive may be controlledbased upon input from the user to move a patient side cart in arelatively easy manner. Further, it may be desirable to provide apatient side cart with controls to drive and move the patient side cartthat are not complex but are instead relatively easy to use.

SUMMARY

Exemplary embodiments of the present disclosure may solve one or more ofthe above-mentioned problems and/or may demonstrate one or more of theabove-mentioned desirable features. Other features and/or advantages maybecome apparent from the description that follows.

In accordance with at least one exemplary embodiment, a patient sidecart for a teleoperated surgical system may include at least onemanipulator portion for holding a surgical instrument and a steeringinterface. The steering interface may include at least one sensorpositioned to sense turning, fore, and aft forces exerted by a user tomove the cart. The steering interface may further include a couplingmechanism to removably couple the steering interface with the patientside cart. The at least one sensor may be placed in signal communicationwith a drive control system of the patient side cart when the steeringinterface is in a coupled state with the patient side cart.

In accordance with another exemplary embodiment, a steering interfacefor a cart including a drive control system may include at least onesensor positioned to sense turning, fore, and aft forces exerted by auser to move the cart. A coupling mechanism may be included in thesteering interface for removably coupling the steering interface withthe patient side cart. At least one sensor may be configured to beplaced in signal communication with the drive control system of the cartwhen the steering interface is in a coupled state with the cart.

In accordance with another exemplary embodiment, a method of moving apatient side cart of a teleoperated surgical system, the patient sidecart including a steering interface and a surgical instrument, mayinclude the step of detecting a force applied to the steering interfacewith a sensor of the steering interface. The method may include a stepof providing a signal from the sensor to a drive system of the patientside cart. The method may include a step of driving at least one wheelof the patient side cart on a basis of the signal provided from thesensor of the steering interface.

Additional objects, features, and/or advantages will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the present disclosureand/or claims. At least some of these objects and advantages may berealized and attained by the elements and combinations particularlypointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the claims; rather the claims should beentitled to their full breadth of scope, including equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be understood from the following detaileddescription, either alone or together with the accompanying drawings.The drawings are included to provide a further understanding of thepresent disclosure, and are incorporated in and constitute a part ofthis specification. The drawings illustrate one or more exemplaryembodiments of the present teachings and together with the descriptionserve to explain certain principles and operation. In the drawings,

FIG. 1 is a diagrammatic view of an exemplary teleoperated surgicalsystem in accordance with at least one exemplary embodiment;

FIG. 2 is a schematic perspective view of an exemplary embodiment of apatient side cart that includes a steering interface;

FIG. 3 is a front perspective view of an exemplary embodiment of asteering interface for a patient side cart;

FIG. 4 is a rear perspective view of the steering interface of FIG. 3;

FIG. 5 is an interior perspective view of an exemplary embodiment of asteering interface;

FIG. 6 is a perspective view of an exemplary embodiment of a sensor fora steering interface;

FIG. 7 is a bottom perspective view of the sensor of FIG. 6;

FIG. 8 is a perspective view of an exemplary embodiment of a sensorblock for a steering interface;

FIG. 9 is a cross-sectional perspective view of an exemplary embodimentof a steering interface and a sensor block mounted within the steeringinterface;

FIG. 10 is a cross-sectional view of an exemplary embodiment of asteering interface and a sensor block mounted within the steeringinterface;

FIG. 11 is a cross-sectional perspective view of an exemplary embodimentof a steering interface;

FIG. 12 is a cross-sectional perspective view of an exemplary embodimentof a steering interface including a contact switch;

FIG. 13 is a perspective view of an exemplary embodiment of a steeringinterface including a calibration data storage device;

FIG. 14 is a schematic block diagram of an exemplary steering interfacesystem connected to a patient side cart;

FIG. 15 is a circuit diagram including a two sensors that each include acomplete Wheatstone bridge, according to an exemplary embodiment; and

FIG. 16 is a circuit diagram including two sensors each having one halfof a Wheatstone bridge, according to an exemplary embodiment.

DETAILED DESCRIPTION

This description and the accompanying drawings that illustrate exemplaryembodiments should not be taken as limiting. Various mechanical,compositional, structural, electrical, and operational changes may bemade without departing from the scope of this description and theinvention as claimed, including equivalents. In some instances,well-known structures and techniques have not been shown or described indetail so as not to obscure the disclosure. Like numbers in two or morefigures represent the same or similar elements. Furthermore, elementsand their associated features that are described in detail withreference to one embodiment may, whenever practical, be included inother embodiments in which they are not specifically shown or described.For example, if an element is described in detail with reference to oneembodiment and is not described with reference to a second embodiment,the element may nevertheless be claimed as included in the secondembodiment.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages, orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about,” to the extent they are not already so modified.Accordingly, unless indicated to the contrary, the numerical parametersset forth in the following specification and attached claims areapproximations that may vary depending upon the desired propertiessought to be obtained. At the very least, and not as an attempt to limitthe application of the doctrine of equivalents to the scope of theclaims, each numerical parameter should at least be construed in lightof the number of reported significant digits and by applying ordinaryrounding techniques.

It is noted that, as used in this specification and the appended claims,the singular forms “a,” “an,” and “the,” and any singular use of anyword, include plural referents unless expressly and unequivocallylimited to one referent. As used herein, the term “include” and itsgrammatical variants are intended to be non-limiting, such thatrecitation of items in a list is not to the exclusion of other likeitems that can be substituted or added to the listed items.

Further, this description's terminology is not intended to limit theinvention. For example, spatially relative terms—such as “beneath”,“below”, “lower”, “above”, “upper”, “proximal”, “distal”, and thelike—may be used to describe one element's or feature's relationship toanother element or feature as illustrated in the figures. Thesespatially relative terms are intended to encompass different positions(i.e., locations) and orientations (i.e., rotational placements) of adevice in use or operation in addition to the position and orientationshown in the figures. For example, if a device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be “above” or “over” the other elements or features.Thus, the exemplary term “below” can encompass both positions andorientations of above and below. A device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

Various exemplary embodiments contemplate a patient side cart of ateleoperated surgical system in which the patient side cart includes asteering interface for a user. The steering interface may permit a userto move the patient side cart in a relatively easy manner without theuse of complex control devices. A steering interface in accordance withvarious exemplary embodiments may include “intelligence” in that theystore various calibration data that can be provided to a controlprocessor that uses drive control algorithms for motor-assisted drivingof the cart. Such data may be used for various purposes, such as tocalibrate devices of the steering interface which may vary to a degreefrom one to another. For instance, data could include calibration datafor one or more sensors that are included in the steering interface.Calibration of a component of a steering interface, such as a forcesensor, may include storing calibration data in a data storage device ofthe steering interface. The calibration may include, for instance, datathat associates a force detected by a force sensor with a signal that adrive system of a cart may use to control movement of a cart. Thecalibration data may associate the detected force with a signal for adrive system through an algorithm, such as through one or moreequations, look up tables, or other functions. The features of theexemplary embodiments described herein may be applied to other wheeledobjects, such as, for example, imaging equipment, operating tables, andother wheeled devices which are intended to move through the applicationof a motive force (e.g., pushing and/or steering forces) by a user.

Further, the intelligence functions of the steering interface may beconfigured to function automatically, such as when a steering interfaceis initially mounted to a cart and connections are made between the cartand steering interface to permit transmittal of data to the cart. Forinstance, the calibration function of a steering interface may functionautomatically when the steering interface is mounted to a cart, causingstored data from a calibration device of the steering interface tocalibrate signals transmitted from one or more force sensors to a drivesystem of the cart.

In various exemplary embodiments, the steering interface may bereplaceable, e.g., in the field, such as when the steering interface orcomponent thereof is damaged or otherwise non-functional. In addition,if one or more components of a steering interface is damaged orotherwise requires repair, the steering interface could be removed sothe component may be repaired or replaced. Recalibration could also beconducted on components of a steering interface once the steeringinterface has been removed so that the steering interface is ready tofunction when the steering interface is attached to a cart. According toan exemplary embodiment, steering interfaces described herein may beused with various carts, including carts of different sizes and/orconfigurations. Further, various exemplary embodiments contemplate asteering interface for a patient side cart of a teleoperated surgicalsystem.

Steering interfaces of the exemplary embodiments described herein may beprovided in various forms. According to one exemplary embodiment, asteering interface for a patient side cart of a teleoperated surgicalsystem may be provided in the form of a handlebar. However, the form orshape of the steering interface for a user of a patient side cart of ateleoperated surgical system is not limited to this exemplaryembodiment. For example, a steering interface for a patient side cartmay be in the form of a plurality of handlebars, one or more handles, asteering wheel, combinations of these interfaces, and other shapes andforms used for steering interfaces.

Teleoperated Surgical System

With reference now to FIG. 1, a teleoperated surgical system 100 isprovided which, in an exemplary embodiment, performs minimally invasivesurgical procedures by interfacing with and controlling a variety ofremotely operated surgical instruments, such as one or moreelectrosurgical instruments 102, as those of ordinary skill in the artare generally familiar. The surgical instruments 102 may be selectedfrom a variety of instruments that are configured to perform varioussurgical procedures, and in accordance with various exemplaryembodiments can have a variety of configurations to implement surgicalprocedures of conventional surgical instruments. Non-limiting examplesof the surgical instruments 102 include, are but not limited to,instruments configured for suturing, stapling, grasping, applyingelectrosurgical energy, and a variety of other instruments with whichthose having ordinary skill in the art are generally familiar.

As illustrated in the schematic view of FIG. 1, the teleoperatedsurgical system 100 includes a patient side cart 110, a surgeon console120, and a control cart 130. In non-limiting exemplary embodiments ofthe teleoperated surgical system, the control cart 130 includes “core”processing equipment, such as core processor 170, and/or other auxiliaryprocessing equipment, which may be incorporated into or physicallysupported at the control cart 130. The control cart 130 may also includeother controls for operating the teleoperated surgical system. As willbe discussed in more detail below, in an exemplary embodiment, signalstransmitted from surgeon console 120 may be transmitted to one or moreprocessors at control cart 130, which may interpret the signals andgenerate commands to be transmitted to the patient side cart 110 tocause manipulation of one or more of surgical instruments and/or patientside manipulators 140 a-140 d to which the surgical instruments 102 arecoupled at the patient side cart 110. It is noted that the systemcomponents in FIG. 1 are not shown in any particular positioning and canbe arranged as desired, with the patient side cart 110 being disposedrelative to the patient so as to affect surgery on the patient. Anon-limiting, exemplary embodiment of a teleoperated surgical systemwith which the principles of the present disclosure may be utilized is ada Vinci® Si (model no. IS3000) commercialized by Intuitive Surgical,Inc. of Sunnyvale, Calif.

In general, the surgeon console 120 receives inputs from a user, e.g., asurgeon, by various input devices, including but not limited to,gripping mechanisms 122 and foot pedals 124, and serves as a mastercontroller by which instruments mounted at the patient side cart 110 actas slaves to implement the desired motions of the surgical instrument(s)102, and accordingly perform the desired surgical procedure. Forexample, while not being limited thereto, the gripping mechanisms 122may act as “master” devices that may control the surgical instruments102, which may act as the corresponding “slave” devices at themanipulator arms 140, and in particular control an end effector and/orwrist of the instrument as those having ordinary skill in the art arefamiliar with. Further, while not being limited thereto, the foot pedals124 may be depressed to provide, for example, monopolar or bipolarelectrosurgical energy to the instrument 102.

In various exemplary embodiments, suitable output units may include, butare not limited to, a viewer or display 126 that allows the surgeon toview a three-dimensional image of the surgical site, for example, duringthe surgical procedure, e.g., via an optical endoscope 103 at thepatient side cart 110. Other output units may include a speaker (orother component capable of transmitting sound), and/or a component withwhich a surgeon is in contact that can vibrate or the like to providehaptic feedback. In various exemplary embodiments, the one or moreoutput units may be part of the surgeon console 120 and signals can betransmitted from the control cart 130 thereto. Although in variousexemplary embodiments, one or more input mechanisms 122, 124 may beintegrated into the surgeon console 120, various other input mechanismsmay be added separately and provided so as to be accessible to thesurgeon during use of the system, but not necessarily integrated intothe surgeon console 120. In the context of the present disclosure, suchadditional input mechanisms are considered part of the surgeon console.

Thus, a “surgeon console” as used herein includes a console thatcomprises one or more input devices 122, 124 that a surgeon canmanipulate to transmit signals, generally through a control cart such as130 to actuate a remotely-controllable kinematic structure (e.g.,surgical instruments 102 mounted at arms 140) at the patient side cart110. The surgeon console 120 may also include one or more output devicesthat can provide feedback to the surgeon. As used herein, it should beunderstood, however, that a surgeon console can include a unit (e.g.,substantially as shown by element 120 in FIG. 1) that integrates thevarious input and output devices, with, for example, a display, but alsocan include separate input and/or output devices that are in signalcommunication with the controllers, such as controllers provided at thecontrol cart and accessible by a surgeon, although not necessarilyintegrated within a unit with various other input devices. As anexample, input units may be provided directly at the control cart 130and may provide input signals to a processor at the control cart. Assuch, a “surgeon console” does not necessarily require all of the inputand output devices to be integrated into a single unit and can includeone or more separate input and/or output devices.

The exemplary embodiment of FIG. 1 illustrates a patient side cart 110with multiple, independently moveable manipulator arms 140 that eachsupports an actuation interface assembly (such as, e.g., 146 shown inFIG. 3) and are configured to hold and manipulate various tools,including, but not limited to, for example, a surgical instrument (e.g.,electrosurgical instruments 102), and an endoscope 103. However, thosehaving ordinary skill in the art will appreciate that other patient sidecart configurations may be used.

Based on the commands input to input devices at, for example, thesurgeon console 120, the patient side cart 110 can position and actuatethe instrument(s) 102 to perform a desired medical procedure via theactuation interface assemblies 146 at the manipulator arms 140. Theactuation interface assemblies 146 are configured to engage withtransmission mechanisms 147 provided at a proximal end of the surgicalinstruments 102 (the general “proximal” and “distal” directions beingshown in FIG. 1 relative to the surgical instrument). The surgicalinstrument 102 and the actuation interface assembly 146 may bemechanically and/or electrically connected to be able to operate theinstrument 102. A patient side cart 110 may include a plurality ofwheels 149 mounted or otherwise attached to the cart 110, such as to abase 148 of the cart 110.

The teleoperated surgical system 100 can include a control system thatreceives and transmits various control signals to and from the patientside cart 110 and the surgeon console 120. The control system cantransmit light and process images (e.g., from an endoscope at thepatient side cart 110) for display, such as, e.g., display 126 at thesurgeon console 120 and/or on a display 132 associated with the controlcart 130.

In exemplary embodiments, the control system may have all controlfunctions integrated in one or more processors, such as a core processor170 at the control cart 130, or additional controllers (not shown) maybe provided as separate units and/or supported (e.g., in shelves) on thecontrol cart 130 for convenience. The latter may be useful, for example,when retrofitting existing control carts to control surgical instrumentsrequiring additional functionality, for example, by providing electricalenergy for use in monopolar and bipolar applications.

One of ordinary skill in the art would recognize that the controllers,e.g., core processor 170, provided at control cart 130 may beimplemented as part of a control system, which, as will be discussed inmore detail below, controls various functions of the present disclosure.One of ordinary skill in the art would recognize that functions andfeatures of the controllers, e.g., core processor 170, may bedistributed over several devices or software components, including, butnot limited to, processors at any of the surgeon console 120, patientside cart 110 and/or other devices incorporating processors therein.Functions and features of the control system, which may include coreprocessor 170, may be distributed across several processing devices.

Patient Side Cart Steering Interface

A teleoperated surgical system, such as system 100, may be used in aparticular location during its use, such as in an operating room. On theother hand, there may be a need to move the teleoperated surgical systemor some of its components. For example, a patient side cart 110 may needto be moved to a desired position during use, such as to locate thepatient side cart 110 so that its surgical instruments 102 arepositioned to perform surgery on a patient when controlled by a surgeonat a surgeon console 120. It also is desirable to move a patient sidecart 100 away from the patient. Such positioning of a patient side cart110 may require moving the patient side cart 110 within a given room ormoving the patient side cart 110 from one room to another.

An exemplary patient side cart may have a weight in the range of onethousand to two thousand pounds, for example. In another example, anexemplary patient side cart may have a weight in the range of, forexample, about 1200 pounds to about 1850 pounds. Without assistance,such a heavy patient side cart might be difficult for a user to move andcontrol during its movement. One way to provide assistance in moving apatient side cart is to include a powered drive system in the patientside cart that is controlled on the basis of input provided by the user.However, a drive system could require several discrete controls thatseparately control a component of the motion of a patient side cart. Forinstance, the controls for a drive system could include a throttlecontrol, a brake control, and/or steering controls each of which a usermay have to manipulate during movement of a patient side cart. Such anarray of various controls could present a user with some difficulty whenmoving a patient side cart, particularly when a user is not familiarwith the drive controls of a patient side cart. Therefore, it may bedesirable to provide a drive control for a patient side cart that iseasy to use and provides input from a user to the patient side cart.

Turning to FIG. 2, an exemplary embodiment of a patient side cart 310 isshown schematically. A patient side cart 310 may be arranged accordingto any of the exemplary embodiments described herein, such as withreference to FIG. 1 described above. For example, a patient side cart310 may include one or more surgical instrument(s) 302 and one or morepatient side manipulator(s) 340 to which the surgical instrument(s) 302are coupled. A patient side cart 310 may include wheels (not shown) onits base to permit movement of the cart. For example, a patient sidecart 310 may include three wheels or four wheels. One or more of thewheels may be driven by a drive system included in the patient side cart310 that provides motive force to the driven wheel(s). For instance, inone exemplary embodiment, wheels in the front of a patient side cart maybe driven while rear wheels are not, with the front of the cart beingwhere the manipulator arms are positioned. In other examples, wheels inthe rear of a patient side cart may be driven or all wheels of a patientside cart may be driven. Wheels that are not driven may be permitted tospin freely as the patient side cart is driven and the wheel contacts aground surface. Wheels may also be turned by steering mechanismsaccording to steering input provided by a user. According to anexemplary embodiment, one or more wheels may have a configurationsimilar to a caster wheel and may be permitted to turn freely.

According to an exemplary embodiment, a patient side cart 310 of ateleoperated surgical system may include a steering interface 300, asshown in FIG. 2. A steering interface 300 may be used to detect forcesapplied by a user to the steering interface 300, which in turn may issuea signal to a controller of a drive system of a patient side cart 310,which causes the patient side cart 310 to be driven and steered in adesired manner. As shown in the example of FIG. 2, a steering interface300 may be attached to a rear of a patient side cart 310, with one ormore surgical instrument(s) 202 being located on a front end of thepatient side cart 310. However, the exemplary embodiments describedherein are not limited to a patient side cart 310 with a steeringinterface 300 attached to a rear, and the steering interface 300 mayinstead be mounted on other portions of a patient side cart 310, such asa front or side of the patient side cart 310.

Turning to FIGS. 3 and 4, an exemplary embodiment of a steeringinterface 300 for a patient side cart of a teleoperated surgery systemis shown. According to the exemplary embodiment shown in FIGS. 3 and 4,a steering interface 300 for a patient side cart of a teleoperatedsurgical system may be provided in the form of a handlebar. Such ahandlebar may have a rounded transverse cross-section and be sized so asto provide a comfortable, yet firm, grip for a user steering the cart.In an exemplary embodiment, the handle 300 may have a maximum lateraldimension (e.g., diameter) D ranging from, for example, about 1 inch toabout 2 inches. In another exemplary embodiment, the handle 300 may havea maximum lateral dimension (e.g., diameter) D of, for example,approximately 1.5 inches. However, steering interfaces of the exemplaryembodiments described herein may be provided in various forms and theform or shape of a steering interface for a user of a patient side cartof a teleoperated surgical system is not limited to this exemplaryembodiment. For example, a steering interface for a patient side cartmay be in the form of a plurality of handlebars, one or more handles, asteering wheel, combinations of these forms, and other shapes and formsused for steering interfaces.

According to an exemplary embodiment, a steering interface 300 may bedetachable from a patient side cart. Configuring a steering interface300 to be detachable permits a user to remove a damaged or otherwisenon-functional steering interface 300 with another steering interface300. For example, as shown in FIGS. 3 and 4, the steering interface 300may include a mounting portion 306 that contacts a patient side cart andattaches the steering interface 300 to the patient side cart. To permita user to replace a steering interface with relative ease, a steeringinterface 300 may include one or more devices to attach the steeringinterface 300 to a patient side cart. As shown in the exemplaryembodiment of FIGS. 3 and 4, the mounting portion 306 of a steeringinterface 300 may include one or more fasteners 307 to attach thesteering interface 300 to a patient side cart. Fasteners 307 may be, forexample, threaded fasteners, such as bolts, or other types of fastenersthat permit a user to detach the mounting portion 306 of a steeringinterface 300 from a patient side cart with relative ease. Therefore,when a user desires to replace a steering interface 300, the user mayunfasten the mounting portion 306 of the steering interface 300 from apatient side cart, such as via the one or more fasteners 307, and attacha second steering interface (not shown) to the patient side cart via themounting portion and fastener(s) of the second steering interface.

As will be described in further detail below, the steering interface 300may have a core/shell configuration, with at least a portion of the corebeing located at in a region of the mounting portion 306 and the outershell being located at least in a region of a left portion 302 of thesteering interface and a right portion 304 of the steering interface.

To use a steering interface 300 of a patient side cart, a user may pushthe steering interface 300 in a direction that the user desires thepatient side cart to move. Such a force may be applied to the steeringinterface 300 while grasping the steering interface 300. For example,when a steering interface 300 is provided in the form of a handlebar, asshown in the exemplary embodiment of FIGS. 3 and 4, a user may grasp aleft portion 302 of the steering interface 300 and a right portion 304of the steering interface 300. When the steering interface 300 isconnected at a rear of a patient side cart 310, as shown in the exampleof FIG. 2, a user may push the steering interface 300 substantially inthe forward direction shown in FIG. 3. The steering interface 300, asdescribed in more detail below, may be configured to detect the forceapplied by the user in the forward direction and provide a signal to acontrol system of a drive system of the patient side cart 310 to movethe patient side cart 310 in the forward direction.

Similarly, when a user wishes to move the patient side cart 310 in arearward direction, the user may pull on the steering interface 300substantially in the rearward direction shown in FIG. 3 so that thesteering interface 300 may detect the force and provide a signal to thecontrol system of the drive system so that the patient side cart 310 ismoved in the rearward direction.

According to an exemplary embodiment, a user may indicate a desire toturn a patient side in a given direction by applying a force to asteering interface of the cart. For instance, a user may apply a lateralforce to a steering interface 300 along directions substantiallyperpendicular to the forward and rearward directions of FIG. 3, whichmay substantially correspond to a direction along a Y direction or axis.

The sensor configuration discussed above for detection of a forceapplied by a user to indicate a desired movement for a patient side cartis one exemplary way of sensing turning and fore/aft steering control,but other techniques also could be employed and sensor configurationsmodified accordingly. For instance, according to another exemplaryembodiment, a user may indicate that the patient side cart should turnby applying more force to one of the left portion 302 and right portion304 of the steering interface 300 than the other of the left portion 302and right portion 304. The steering interface 300 can detect the appliedforces and issue a signal to the control system of the drive system,which commands the drive system to turn in the direction desired by theuser.

As noted above, the steering interface 300 may include one or moresensors configured to detect forces applied to the steering interface300 by a user. Turning to the exemplary embodiment of FIG. 5, thesteering interface 300 is depicted with its outer shell removed to showinternal components of the steering interface 300, including a coreportion 310. The core portion 310 may be constructed from a materialcapable of withstanding relatively high stress. For example, the coreportion 310 may be manufactured from a high strength steel, but otherhigh strength materials also may be used without departing from thescope of the present disclosure. In an exemplary embodiment, the outershell may be manufactured from, for example, a metal or metal alloy,such as aluminum. According to an exemplary embodiment, an outer shellmay include materials at locations corresponding to where a user maytouch or grasp the handle to provide a desirable tactile feel for auser. For instance, an outer shell may include rubber, plastic, or othermaterials at such locations.

The core portion 310 of the steering interface 300 may include one ormore sensors configured to transmit signals to a drive system (notshown) of the cart to move the cart upon input by a user at the steeringinterface 300. For example, as shown in FIG. 5, a steering interface 300may include a first sensor 320 mounted in a left portion 302 of thesteering interface 300 and a second sensor 322 mounted in a rightportion 304 of the steering interface 300. In other words, sensors 320,322 may be provided in substantially opposite portions of a steeringinterface 300. By providing a steering interface 300 with sensors 320,322 in different portions of the interface 300, a user mayadvantageously position themselves at differing positions relative tothe steering interface 300 and apply a force with one or both hands andthus apply a force to one or both of sensors 320, 322 to achieve thesame result with respect to the steering and movement of the cart. Sucha configuration can be helpful, for instance, to facilitate the abilityof a user to observe the environment in front of the cart when a user ispositioned at the rear of the cart. If the user were required to bepositioned directly behind the cart to operate the steering interface300, the user's view may be blocked by the cart, such as by themanipulator arm portion of the cart. By permitting a user to bepositioned relatively to one side of the steering interface 300, theuser may stand to one side of the cart, use one hand on the steeringinterface 300, and have an improved view of the environment in front ofthe cart.

Sensors 320, 322 may be configured to detect forces applied to thesteering interface 300 by a user in the forward and rearward directionsof FIG. 3 and may be configured to detect forces applied by a user tothe steering interface 300 to turn a patient side cart 310. The forwardand rearward directions of FIG. 3 may substantially correspond todirections along an X direction or axis and directions substantiallyperpendicular to the forward and rearward directions of FIG. 3 maysubstantially correspond to directions along a Y direction or axis.

Turning to FIG. 6, an exemplary embodiment of a first sensor 320 isshown. Although the following discussion concerns the structures andfeatures of first sensor 320, which may be mounted at the left portion302 of a steering interface 300, second sensor 322, which may be mountedat the right portion 304 of the steering interface 300, may have thesame features and structures as first sensor 320.

Because forces applied by a user may include components in the X and/orY direction indicated in FIG. 5, sensor 320 may include features todetect forces in one or more directions. According to an exemplaryembodiment, sensor 320 may include features to detect forces in the Xand Y directions indicated in FIGS. 5 and 6. For example, sensor 320 mayinclude a first detection device 323 to measure forces applied by a useralong the X direction of FIGS. 5 and 6 and a second detection device 324to measure forces applied by a user along the Y direction of FIGS. 5 and6. As indicated in FIGS. 5 and 6, the X direction and Y direction may beorthogonal to one another. Therefore, even if a force applied by a userto a steering interface 300 is not perfectly aligned with either of theX and Y directions, the components of the applied force may be measuredin the X and Y directions.

In various exemplary embodiments, sensors used in a steering interfacealso may be capable of detecting forces in a vertical Z direction (notshown in the embodiments of FIGS. 5 and 6), which is orthogonal to the Xand Y directions. However, sensors capable of detecting forces in avertical Z direction are optional and a steering interface may includeonly sensors that detect forces in the X and Y directions.

Detection devices 323, 324 may be configured to detect relatively smallforces applied by a user to a steering interface 300, such as when auser pushes, pulls, or moves sideways the steering interface 300 toindicate a desire to move a patient side cart. For example, detectiondevices 323, 324 may be sufficiently sensitive to detect a force appliedby a person to a steering interface 300. For example, detection devices323, 324 may be sensitive enough to detect a force applied by a personhaving the weight and size of an average adult. According to anexemplary embodiment, detection devices 323, 324 may detect forcesranging from, for example, from approximately 0.1 lbs. to approximately100 lbs. According to another exemplary embodiment, detection devices323, 324 may detect forces ranging from, for example, from approximately0.4 lbs. to approximately 25 lbs. According to exemplary embodiments,the range of force sensitivity of the sensors may be selected based onfactors such as, for example, the size and/or weight of the cart and/orthe exertion desired to be required by a user during movement of thecart.

Detection devices 323, 324 of sensor 320 may be components configured todetect a force applied to sensor 320 and provide an electrical signalcorresponding to the applied force. For instance, detection devices 323,324 may be strain gauges. Each detection device 323, 324 may be a singledevice to measure an applied force or may include a plurality of devicesto detect an applied force.

According to an exemplary embodiment, detection devices 323, 324 mayeach include a plurality of devices to detect applied forces in the Xand Y directions so that sensors 320, 322 have redundant detectiondevices in case one of the detection devices of a sensor fails. Forexample, detection device 323 and/or detection device 324 may includeprimary and secondary detection components (not shown) in each of the Xand Y directions to advantageously provide redundant detection devices.

Thus, if one of the primary or secondary detection components of adetection device 323, 324 should fail (including the connections orcontrol electronics for one of the primary or secondary detectioncomponents), the detection component 323, 324 will have the other of theprimary and secondary detection component functioning and will still beable to perform its function of detecting forces applied to a steeringinterface 300. In other words, the redundant primary or secondarydetection components of a detection device 323, 324 may serve as asafety precaution that may prevent or minimize unanticipated cartmovement, for example, by restricting cart movement if primary andsecondary detection components are not in agreement. According toanother exemplary embodiment, a secondary detection component may beprovided as a redundant backup to the primary detection component, orvice versa. In this case, if one of the primary or secondary detectioncomponents of a detection device 323, 324 should fail, an entire sensor320, 322 or steering interface 300 need not be replaced. In a furtherexample, detection device 223 may include a primary strain gauge and asecondary strain gauge to detect forces in the X direction and detectiondevice 224 may include a primary strain gauge and a secondary straingauge to detect forces in the Y direction.

According to an exemplary embodiment, sensor 320 may further include oneor more electrical terminals 326 that may be used to transmit electricalsignals to and from the sensor 320. As shown in the example of FIG. 7, abottom surface 327 of sensor 320 may include one or more mounts 328 toattach sensor 320 to a steering interface 300, such as a core portion310 of a steering interface 300.

Because sensors 320, 322 are subjected to forces and strain when a userapplies forces to a steering interface 300, it is possible that thesensors 320, 322 may become damaged, in particular because some straingauge sensors are designed to detect relatively small displacements(e.g., forces) and the forces applied to the steering interface may berelatively large. To address this issue, sensors 320, 322 may be mountedin a steering interface 300 with one or more devices to provide a degreeof protection to sensors 320, 322 by limiting excess forces on thesensors that could potentially damage the sensors 320, 322. Suchprotective devices can be any of a variety of devices that are compliantand bend. In addition, protective devices may limit the amount ofmovement that a sensor is permitted. In other words, one or moreprotective devices can be used to translate a relatively largedisplacement applied to a steering interface into a relatively smalldisplacement of a sensor 320, 322. Such devices may include, forexample, springs, bars or rods configured to deflect (e.g., throughbending and/or torsion), elastomer material, and other types of devicesconfigured to provide additional compliance around the sensors 320, 322when the shell portion 312 moves relative to the core portion 310.

For example, as shown in the exemplary embodiment of FIG. 8, sensor 320may be mounted with one or more springs 332 configured and arrangedrelative to the sensor 320 to provide a degree of protection to sensor320. Sensor 320, a sensor housing 331, and springs 332 together may forma sensor block 330, which may be mounted within a steering interface 300via the spring(s) 332 so that the spring(s) provide additionalcompliance between the sensor 320 and the remainder of the steeringinterface 300.

For instance, as shown in the exemplary embodiment of FIG. 9, sensorblock 330 (shown in section in FIG. 9) may be included in a steeringinterface 300 by mounting sensor 320 to a core portion 310 of thesteering interface 300 and by attaching one or more springs 332 to acover portion 312 of the steering interface 300 via one or more springmounts 334. In other words, spring(s) 332 may connect sensor 320 to thecover portion 312. A cover portion 312 may be, for example, in the formof a shell around the core portion 310 (as shown in the example of FIG.9), in the form of one more flat or curved surfaces, or other forms of acover.

According to an exemplary embodiment, the core portion 310 and the coverportion 312 of the steering interface 200 may lack structuralconnections aside from those provided by the sensor blocks 330 ofsensors 320, 322. In such an embodiment, therefore, the structuralconnections provided by the sensor blocks 330 of the one or more sensorsof a steering interface 300 may provide the only connections between thecore portion 310 and the cover portion 312 of a steering interface 300.In other words, if a steering interface 300 includes a single sensorblock 330, the sensor block 330 may provide the sole connection betweenthe core portion 310 and the cover portion 12. If a steering interface300 includes a plurality of sensor blocks 330, the sensor blocks 330 maycollectively provide the sole connection between the core portion 310and the cover portion 312. For instance, connection provided byspring(s) 332, housing 331, and spring mount(s) 334 of a sensor block330 may provide the sole connection between a core portion 310 and acover portion 312. In this manner, the cover portion 312 and the coreportion 310 may be considered to be “floating” relative to one another.According to an exemplary embodiment, the cover portion 312 may beconsidered to be “floating” relative to the core portion 310 due to thesuspension of the cover portion 312 from the core portion 310 by thesensor block(s) 330. For instance, if the core portion 310 is connectedto a patient side cart, the cover portion 312 may seem to move relativeto the core portion 310. According to another exemplary embodiment, thecore portion 310 may be considered to be floating relative to the coverportion 312, such as when the cover portion 312 is connected to apatient side cart instead of the core portion 310.

When a force is applied to a steering interface, for example to indicatea user's desired direction of movement of the cart, the force may beapplied to the cover portion 312 and transmitted to the sensor 320 viaspring(s) 332 due to the suspension structure provided by the sensorblock(s) 330 arranged between the core portion 310 and the cover portion312. Because spring(s) 332 are relatively flexible elements, spring(s)332 may advantageously allow additional motion of the cover portion 312relative to the core portion 310 for a same user-applied force. As aresult, the sensor block 330 may be mounted between the core portion 310and the cover portion 312 of the steering interface 300, with thespring(s) 332 serving to provide additional compliance to the steeringinterface 300.

As shown in FIG. 9, in various exemplary embodiments, a gap having adistance A may be provided between the core portion 310 and the coverportion 312. The gap may be provided between the core portion 310 andthe cover portion 312 in all directions. The gap may have a distance A,for example, ranging from about 0.04 in. to about 0.07 in. In anotherexample, the gap may have a distance A ranging from about 0.045 in. toabout 0.065 in. A relatively small gap between the core portion 310 andthe cover portion 312 may permit the cover portion 312 and the coreportion 310 to move relative to one another. Such relative movement mayenable forces applied by a user to be relatively easily transmitted tothe sensors 320, 322. Providing a steering interface 300 with suchconstruction may advantageously avoid a steering interface that isrelatively “soft” (e.g., permits a higher degree of relatively movementbetween the core portion 310 and the cover portion 312), which couldresult in an undesirable feedback loop that may cause a significantchange in an applied force to a sensor and result in the motion of apatient side cart to unintentionally oscillate. Further, according to anexemplary embodiment, the gap is sufficiently small so that movementbetween the core portion 310 and the cover portion 312 is imperceptibleor negligible to human senses. Thus, a user might not notice movement ofthe cover portion 312 relative to the core portion 310, which in turnmay impart a sturdy, high quality feel to the user during application offorces to the steering interface while driving the cart. Thus, thesteering interface 300 may be able to provide its function of detectingforces applied by a user while also presenting an appearance of solidconstruction and craftsmanship.

According to an exemplary embodiment, a steering interface 300 mayinclude mechanical stops to limit the amount of relative movementbetween the core portion 310 and the cover portion 312 due to a forceapplied by a user to the steering interface 300. Thus, the mechanicalstops may limit the amount of force and strain applied to sensors.Turning to the partial, internal plan view of FIG. 10, which shows thecover portion 312 of the steering interface 300 is suspended from a coreportion 310 by a sensor block 330 and its spring(s) 332, as describedabove, end portion 314 of the core portion 310 may include a projection316 that extends into a recess 317 formed within the cover portion 312so that a gap 318 is provided between the projection 316 and an innersurface portion of the cover portion 312 surrounding the recess 317. Inaddition, a gap 315 may be provided between the end portion 314 of thecore portion 310 and an inner wall 319 of the cover portion 312.

When a relatively large force is applied to a steering interface 300,the applied force may be applied to the sensor 320 of the sensor block330. This may result in a large strain being applied to the sensor 320,which could cause damage to the sensor 320 if the strain is excessive.The relatively large force and strain may also move the core portion 310and the cover portion 312 relative to one another, potentially causingthe projection 316 to contact the wall of the cover portion 312 formingthe recess 317. Alternatively, or in addition to this movement, the endportion 314 may come into contact with the inner surface portion 319.When the projection 316 contacts the inner surface portion of the coverportion 312 forming the recess 317 and/or the end portion 314 contactsthe inner wall 319, further movement between the core portion 310 andthe cover portion 312 is ceased so that the amount of strain applied tosensor 320 is limited. As a result, overloading and damage caused to thesensor 320 by large forces and strains may be minimized or prevented. Inaddition, springs 332 provide enhanced compliance for a sensor block330. Thus, a sensor block 330 may have a cost effective design thatpermits reasonable manufacturing tolerances in gaps between core portion310 and cover portion 312, while limiting displacement of a sensor 320to a relatively small amount. For example, in an exemplary embodiment, amovement of about 0.065 inches between core portion 310 and coverportion 312 may result in a displacement of sensor 320 of about 0.010inches.

According to an exemplary embodiment, sensors 320, 322 and theirrespective sensor blocks 330 may be contained within a steeringinterface 300 so that the sensors 320, 322 and sensor blocks 330 arecompletely surrounded. As a result, the sensors 320, 322 and sensorblocks may be covered and not exposed on an exterior surface of thesteering interface 300. For instance, cover portion 312 of a steeringinterface 300 may completely surround sensors 320, 322 so that thesensors are not exposed, for example to the external environment. Inanother example, a portion of sensors 320, 322 may be exposed on anexterior surface of a steering interface 300 so that at least a portionof the sensors 320, 322 are able to be viewed by a user.

According to an exemplary embodiment, a steering interface 300 mayinclude one or more devices to control the flexibility and movement ofthe steering interface 300 when a user applies a force to the steeringinterface 300. Such devices may be used, for example, to affect how thesteering interface 300 moves relative to a patient side cart that thesteering interface 300 is attached to when a user applies a force to thesteering interface 300. Such devices may be provided in addition to thesensor blocks 330 described above, including the spring(s) 332 of asensor block 330.

Turning to FIG. 11, an exemplary embodiment of a steering interface 300is shown in which a stabilizing device 340 is located between a coreportion 310 and a cover portion 312 of the steering interface 300.According to an exemplary embodiment, a stabilizing device 340 mayprevent motion of a steering interface in a direction other than an X orY direction. Further, the stabilizing device 340 may be provided tocontrol the amount of movement of cover portion 312 relative to coreportion 310. For instance, a user may apply a rotational moment M tosteering interface 300, as shown in the exemplary embodiment of FIG. 11.If a steering interface 300 moves in the direction indicated by moment Mrelative to a patient side cart, a user may have an impression that apatient side cart should respond in some manner as a result of themovement of the steering interface 300. Accordingly, using a stabilizingdevice to minimize or prevent such movement can avoid a user mistakenlybelieving that the cart will respond to such input at the steeringinterface 300. In addition, if the steering interface 300 moves in thedirection indicated by moment M relative to a patient side cart that thesteering interface 300 is mounted to, the user may have the sensationthat the steering interface 300 is loose or not well made, particularlyif the motion is abrupt and not smooth.

The stabilizing device 340 may act to resist motions that result when auser applies a force to a steering interface 300, which may cause thesteering interface 300 to move in a direction away from its initialposition (e.g., in the direction caused by moment M in FIG. 11), and amotion that results when the user releases the applied force, which maycause the steering interface 300 to move in a direction toward itsinitial position. For example, a stabilizing device 340 may resistmotion by shunting an amount force ranging from, for example, about 10%to about 15% of the applied force to the core portion 310. Further, thisshunting function of a stabilizing device 340 may act to permit motionsof a steering interface substantially in linear directions along the X,Y, and Z directions. By acting in a manner that resists these motions, astabilizing device 340 may permit the motions to occur but in a mannerthat results in smooth motions that are ergonomically desirable to auser, rather than abrupt, jerky motions. As shown in the exemplaryembodiment of FIG. 11, an attenuating device 340 may be, for example, acoil spring mounted between the core portion 310 and the cover portion312 of a steering interface 200. In a further example, a spring may be amachined spring or any of a variety of shock absorption mechanisms withwhich those having skill in the art have familiarity. Other mechanismsmay be used as a stabilizing device other than springs. In an exemplaryembodiment, a stabilizing device 340 may be provided by using a pair ofpermanent magnets.

According to an exemplary embodiment, a steering interface 300 mayinclude a device to send a signal to a drive control system of a patientside cart to activate motion for the cart. For instance, althoughsensor(s) of a steering interface may always send signals regardingforces applied to the steering interface, it may be desirable to providea device that provides a signal to indicate that motion of a patientside cart should not occur to prevent inadvertent motion of a cart, evenif sensor(s) are indicating that a force is being applied to thesteering interface. In other words, a steering interface may include asecond device that issues a second signal that is independent to a firstsignal issued by sensor(s) of the steering interface. If a force appliedto a second device of a steering interface has a sufficient magnitude,the second device may issue a signal indicating that the applied forcerepresents a desired movement. Otherwise, if the force applied to thesecond device is not sufficient, the second device will not issue asignal to indicate that the cart should move. Such a device may providea degree of safety by preventing inadvertent motion of a cart whensignals are being issued from sensor(s) of the steering interface 300 tothe controller for the drive system of a cart and a user is not applyinga force to the steering interface 300 or a force applied to the steeringinterface 300 does not represent a desired motion for the cart.

Turning to FIG. 12, an example of a steering interface 300 is shown thatincludes a contact switch 352 and a contact trigger 350. The contactswitch 352 and contact trigger 350 may be mounted within the steeringinterface 300 to permit relative movement between the contact switch 352and the contact trigger 350. In particular, a contact trigger 350 and acontact switch 352 may both be mounted in a cover portion 312, with atleast a portion of the contact trigger 350 exposed on an outer surfaceof the cover portion 312 so that a user may press the exposed portion ofthe contact trigger 350 to cause the contact trigger 350 to moverelative to the contact switch 352 and cause engagement between thetrigger 350 and switch 352.

When a user applies a force to a steering interface 300, relative motionmay occur between a core portion 310 and a cover portion 312 of thesteering interface 300 and sensor(s) 320 of the steering interface 300may issue a signal indicating the applied force. However, such anapplied force may not result in movement of the cart if trigger 350 isnot properly engaged. To indicate a desired movement for a patient sidecart, a contact trigger 350 may be pressed to cause engagement betweenthe contact trigger 350 and the contact switch 352. When a sufficientforce is applied to the contact trigger 350 to cause engagement betweenthe trigger 350 and the switch 352, the contact switch 352 may issue asignal to a controller or drive system of a patient side cart toindicate that the patient side cart should move according to a signalissued from sensor(s) of the steering interface. Thus, the contactswitch 352 and the contact trigger 350 may serve as a “dead man's”switch so that motion of a patient side cart is permitted when a userapplies a force to a steering interface 300 and presses the trigger 350,but motion is not permitted when the user releases the trigger 350 ofthe steering interface 300 or otherwise does not apply a force to thetrigger 350.

When the contact switch 352 and the contact trigger 350 are not engaged,the steering interface 300, such as the contact switch 352, may issue asignal indicating that a patient side cart should not move according toa signal issued by sensor(s) of the steering interface 300 so thatinadvertent motion of the cart is avoided. Alternatively, when contactswitch 352 and contact trigger 350 are not engaged, no signal may beissued from the steering interface 300, such as from the contact switch352, to indicate that a patient side cart should move, and the absenceof such a signal may be interpreted by a controller or drive system of acart that motion should not occur.

In a further example, at least one of the contact switch 352 and thecontact trigger 350 may be mounted such that the contact trigger 350 isbiased to an “off” position when a user does not apply a force to thecontract trigger 350. In an exemplary embodiment, the contact trigger350 may be mounted using one or more leaf springs 354, although suchbiasing devices are exemplary and non-limiting only. In anotherexemplary embodiment, the contact trigger 350 may be mounted using apivoting lever with a return spring (not shown), such as a coil spring,a spring loaded pushbutton, or other structure including an elasticallydeformable structure.

A steering interface 300 may include a plurality of contact switches 352and contact triggers 350. For example, each of the left portion 302 andthe right portion 304 of a steering interface 300 may include a contactswitch 352 and a contact trigger 350 so that a user may press either atrigger of the left portion 302 or a trigger of the right portion 304 ofthe steering interface 300 to activate motion of a patient side cartthat the steering interface 300 is mounted to. In an alternativeexemplary embodiment, the steering interface 300 may be configured torequire more than one of the contact triggers to be actuated to activatemotion of the cart. Further, trigger 350 need not be in the form of amechanical contact but may take the form of other switch devices used inthe art.

Sensors 320, 322 used in the sensor blocks 330 of a steering interface300 may vary from one another and provide outputs that differ from oneanother. This may require calibration of the sensors 320, 322 relativeto a controller for a drive system of a patient side cart, particularlywhen one steering interface is removed and replaced with anothersteering interface that has different sensors. To address this issue, asteering interface 300 may include a calibration device so that when thesteering interface 300 is mounted to a patient side cart and thecomponents of the steering interface 300 are connected to the controllerfor the drive system of the cart, the output from the sensors isautomatically calibrated without additional effort from the user. Forexample, a steering interface 300 may include a calibration data storagedevice 360, as shown in the exemplary embodiment of FIG. 13.

A calibration data storage device 360 may be, for example, anelectrically erasable programmable read-only memory (EEPROM) device,such as, for example, flash memory or another type of memory that storescalibration data. As will be discussed below, the calibration device 360may be placed in signal connection with a controller of a drive systemfor a patient side cart when a steering interface 300 is mounted to thecart. In addition, connections for the sensor blocks 330, such aselectrical lines or wires, may extend along a side portion 362 of asteering interface 300 so that connections are made between the sensors320, 322 of the sensor blocks 330 when the steering interface 200 ismounted to the cart.

FIG. 14 depicts a schematic block diagram of a steering interface systemin a connected state with a patient side cart, according to an exemplaryembodiment. As shown in FIG. 14, when a steering interface 300 ismounted to a patient side cart 1510 (which in various exemplaryembodiments can be configured like cart 110 or 210 in the exemplaryembodiment of FIG. 1), sensors 220, 222 can be placed in signalconnection with the cart 110, which may include a control processor fora drive system, as mentioned above. Connections may also be made betweenthe cart and contact switches 352 in the steering interface 300 so thatwhen a user applies a force to the trigger 350 of the steering interface300 sufficient to engage a contact switch with a contact trigger 350, asignal may be issued from the steering interface 300 to the cart 1510,such as a signal from at least one of the contact switches 352, toindicate that a drive system of the cart 1510 should act to move thecart 1510 according to signals from sensors 320, 322. Further, aconnection may be made between a calibration device 360 and the cart1510 so that calibration data may be provided to the controller when thesteering interface 300 is mounted to the cart 1510. Signals providedfrom the steering interface 300 to the cart 1510 may be amplified by adevice of the cart 1510. In addition, cart 1510 may include ananalog/digital converter to condition any signals received from thesteering interface 300, as may be required.

The sensors 320, 322 of a steering interface 300 are designed to detecta force applied by a user to the steering interface 300. As discussedabove, sensors 320, 322 may be strain gauges that detect the amount ofstrain applied to the sensors 320, 322 and provide a correspondingsignal. One design for a strain gauge includes a Wheatstone bridge. FIG.15 depicts a circuit diagram including a first sensor 375 and a secondsensor 377. Each of first sensor 374 and second sensor 377 includes acomplete Wheatstone bridge, with the complete Wheatstone bridgeincluding four sensor elements 370, according to an exemplaryembodiment. The circuit further includes an amplifier 374 for eachsensor and a component 376 to measure the voltage across the circuit.Numerals 371 refer to resistances due to cables and/or connectors. Inthe circuit shown in FIG. 15, resistances 371 due to cables and/orconnectors cause relatively small errors in a sensor response. However,these errors from resistances 371 can be compensated and removed by theamplifiers 374, which may form a differential bridge amplifier.

Configurations using complete Wheatstone bridges, as shown in theexemplary embodiment of FIG. 15, result in sensors 375, 377 that eachinclude four sensor elements 370. If a device, such as a handle in oneof the exemplary embodiments discussed herein, include sensors for eachof the X and Y directions at each end of the handle, the configurationresults in a total of sixteen sensor elements 370 for the device.Further, if a redundant set of sensors is provided, the total number ofsensor elements 370 doubles to thirty-two.

One consideration for sensors 320, 322 of a steering interface 300 isthat the sensors 320, 322 are being used to measure a force applied by aperson that is used by a cart drive control system to provide motion tothe cart. In such an application, the sensors 320, 322 need not requirethe accuracy of other applications in which such sensors may beemployed, such as for example making weight measurements or othersensitive force measurements. Accordingly, each sensor 320, 322 need nothave that accuracy of a sensor that includes the configuration shown inFIG. 15. Instead, sensors 320, 322 may be less accurate, whichadvantageously permits an arrangement of the sensors that may be lesscostly. For instance, if strain gauges are used, sensors 320, 322 mayhave the configuration shown in the exemplary embodiment of FIG. 16.

As shown in the exemplary embodiment of FIG. 16, a Wheatstone bridge maybe split so that sensor 320 includes two sensor elements 370 of theWheatstone bridge (one half of the Wheatstone bridge) and sensor 322includes the other two sensor elements 372 of the Wheatstone bridge (theother half of the Wheatstone bridge). The configuration shown in FIG. 16may further include an amplifier 374 and a component 376 to measure thevoltage across the circuit of FIG. 16. Thus, the total number of sensorelements 370, 372 utilized by a device, such as a handle, may be cut inhalf, which advantageously reduces the cost to manufacture the device.Further, an additional cost savings may be provided by using feweramplifiers 374 because only one amplifier 374 could be used.

A potential consequence of using fewer sensor elements 370, 372 for eachsensor 320, 322 is that there may be larger errors in sensor outputs.For instance, resistances 371 due to cables and/or connectors mayproduce errors that are not removed by the amplifier 374 shown in theexemplary embodiment of FIG. 16. Although a configuration using a splitWheatstone bridge, as shown in the exemplary embodiment of FIG. 16, mayresult in sensors 320, 322 that are less accurate than sensors havingthe configuration of FIG. 15, sensors 320, 322 may be sufficientlyaccurate to detect forces applied by a person to a steering interface300. However, according to an exemplary embodiment, the accuracy of asplit Wheatstone bridge may be enhanced. For instance, errors producedby a split Wheatstone bridge may be reduced by, for example, poweringthe bridge with four pairs of wires instead of a single pair of wires toreduce error from cable resistance, using four pairs of connectorcontacts instead of a single pair of connector contacts to reduceconnector error, using corrosion resistant material for connectorscontacts to reduce error from long term aging of the connector contact,specifying the lengths of cables for sensors 320, 322 to besubstantially the same length to have substantially the same cableresistance to reduce error to due differences in cable resistancebetween the sensors 320, 322, and/or removing residual cable and/orconnector resistance via calibration values stored in a device, such ascalibration values stored in calibration data storage device 360discussed above.

According to another embodiment, a patient side cart may include a kickplate. As shown in the exemplary embodiment of FIG. 2, a kick plate 303having a sensor may be located at the rear of a patient side cart, e.g.,the side of the cart where the steering interface is located. A steeringinterface 300 may be designed according to a situation when a user ispushing off of a ground surface to apply a force to the steeringinterface 300. However, if a user puts a foot on the back of a patientside cart in an attempt to help move the cart forward, whilesimultaneously holding the steering interface 300, there may be atendency to pull back on the steering interface in the X (aft)direction. In this situation, since the force applied to the steeringinterface 300 is in the X (aft) direction, the cart would move backwardin the aft direction toward the user, even though the user is attemptingto move the cart forward by using the user's foot. To prevent thissituation, the kick plate 303 can be configured to send a signal to stoppower to drive the cart when a user engages or strikes the kick plate303. According to an exemplary embodiment, kick plate 320 may disablemovement of a cart if both kick plate 320 is pressed and the cart ismoving in a backwards direction.

By providing a steering interface that detects forces applied by a userin a simple manner, a user may advantageously move a patient side cartthat the steering interface is attached to with relative ease. Forinstance, the cart may include a drive system to move the relativelylarge weight of the patient side cart without requiring the user toprovide a force necessary to move the patient side cart withoutassistance. In addition, the steering interface may provide a simpleuser interface that detects the forces applied by the user to thesteering interface so that a control system may in turn determine whichdirection the patient side cart should be driven without requiring theuser to interact with multiple, complex controls. Further, the steeringinterface may advantageously provide a user with a positive feel aboutthe craftsmanship of the steering interface and the patient side cartvia its solid construction and relatively smooth movements.

Exemplary embodiments, including the various operational methodsdescribed herein, can be implemented in computing hardware (computingapparatus) and/or software, such as (in a non-limiting example) anycomputer that can store, retrieve, process and/or output data and/orcommunicate with other computers. The results produced can be displayedon a display of the computing hardware. One or more programs/softwarecomprising algorithms to affect the various responses and signalprocessing in accordance with various exemplary embodiments of thepresent disclosure can be implemented by a processor, such as datainterface module, of or in conjunction with the control cart includingcore processor and may be recorded on computer-readable media includingcomputer-readable recording and/or storage media. Examples of thecomputer-readable recording media include a magnetic recordingapparatus, an optical disk, a magneto-optical disk, and/or asemiconductor memory (for example, RAM, ROM, etc.). Examples of themagnetic recording apparatus include a hard disk device (HDD), aflexible disk (FD), and a magnetic tape (MT). Examples of the opticaldisk include a DVD (Digital Versatile Disc), a DVD-RAM, a CD-ROM(Compact Disc-Read Only Memory), and a CD-R (Recordable)/RW.

Further modifications and alternative embodiments will be apparent tothose of ordinary skill in the art in view of the disclosure herein. Forexample, the systems and the methods may include additional componentsor steps that were omitted from the diagrams and description for clarityof operation. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the present teachings. It isto be understood that the various embodiments shown and described hereinare to be taken as exemplary. Elements and materials, and arrangementsof those elements and materials, may be substituted for thoseillustrated and described herein, parts and processes may be reversed,and certain features of the present teachings may be utilizedindependently, all as would be apparent to one skilled in the art afterhaving the benefit of the description herein. Changes may be made in theelements described herein without departing from the spirit and scope ofthe present teachings and following claims.

It is to be understood that the particular examples and embodiments setforth herein are non-limiting, and modifications to structure,dimensions, materials, and methodologies may be made without departingfrom the scope of the present teachings.

Other embodiments in accordance with the present disclosure will beapparent to those skilled in the art from consideration of thespecification and practice of the invention disclosed herein. It isintended that the specification and examples be considered as exemplaryonly, with a true scope and spirit being indicated by the followingclaims.

What is claimed is:
 1. A surgical system cart comprising: a surgicalinstrument manipulator; a steering interface comprising a graspingsurface; a steering sensor positioned to sense a first force exerted onthe grasping surface; a stop sensor configured to sense a second force;and a drive control system operably coupled to the steering sensor andthe stop sensor, wherein in an operational state, the drive controlsystem: transmits drive power to move the cart in a first direction ofmotion in response to the steering sensor sensing the first force, andstops drive power to the cart in response to the stop sensor sensing thesecond force exerted in a direction opposite to the first direction ofmotion.
 2. The surgical system cart of claim 1, wherein in theoperational state, the drive control system stops drive power to thecart in response to the stop sensor sensing the second force while thesteering sensor is sensing the first force.
 3. The surgical system cartof claim 1, wherein in the operational state, the drive control systemstops movement of the cart in response to the second force applied tothe stop sensor while the first direction of motion is toward a usergrasping the grasping surface.
 4. The surgical system cart of claim 1:wherein the first force comprises one or more of a turning force on thecart, a forward motion force on the cart, and an aft motion force on thecart; and wherein the first direction of motion corresponds to the firstforce and comprises one or more of a turning motion of the cart, aforward motion of the cart, and an aft motion of the cart.
 5. Thesurgical system cart of claim 1, wherein the stop sensor comprises akick plate.
 6. The surgical system cart of claim 5, wherein the steeringinterface and the kick plate are located on a same side of the cart. 7.The surgical system cart of claim 1, wherein the stop sensor comprises akick plate located on the cart at a position accessible by a foot of auser grasping the grasping surface.
 8. The surgical system cart of claim7, wherein the steering interface and the kick plate are located on asame side of the cart.
 9. The surgical system cart of claim 1, whereinthe steering sensor is positioned to sense the first force exerted onthe grasping surface by a user's hand.
 10. The surgical system cart ofclaim 1, wherein the steering sensor comprises two or more redundantsensors.
 11. The surgical system cart of claim 10, wherein the two ormore redundant sensors are positioned at opposite sides of the graspingsurface in positions corresponding to locations of the grasping surfacefor placement of a user's right and left hands during steering of thecart.
 12. The surgical system cart of claim 1, wherein the steeringinterface is removably coupled with the cart.
 13. The surgical systemcart of claim 1, wherein the steering sensor comprises a strain gauge.14. The surgical system cart of claim 1: wherein the cart furthercomprises one or more wheels; and wherein the drive control system isoperably coupled to transmit the drive power to the or each wheel tomove the cart in the first direction of motion.
 15. A method ofcontrolling movement of a surgical system cart, comprising: detecting afirst force exerted on a grasping surface of a steering interface of thecart; providing drive power to move the cart in a direction of motion inresponse to detecting the first force; detecting a second force exertedon the cart in a direction generally opposite to the direction of motionof the cart; and ceasing the drive power to the cart in response todetecting the second force.
 16. The method of claim 15, wherein theceasing of the drive power occurs while the detecting of the first forceoccurs.
 17. The method of claim 15: wherein the first force comprisesone or more of a turning force on the cart, a forward motion force onthe cart, and an aft motion force on the cart; and wherein the directionof motion corresponds to the first force and comprises one or more of aturning motion of the cart, a forward motion of the cart, and an aftmotion of the cart.
 18. The method of claim 15, wherein the first forceis exerted on the grasping surface by a user's hand.
 19. The method ofclaim 15, wherein the second force is exerted on a kick plate by auser's foot.
 20. The method of claim 15, wherein the first force isexerted by a hand of a user and the second force is exerted by a foot ofthe user.